The invention relates to a process and an apparatus for automatically exchanging yarn packages and spool cores at a spinning unit of a machine having a plurality of spinning units which each contain devices for the spinning of two prestrengthened yarns and devices for winding these two yarns, as a double yarn, onto a spool core, these packages serving as feeding packages for a subsequent twisting operation.
It is known (German Published Examined Application - DE-A No. 36 34 464), in the case of an exchange of yarn packages and spool cores, or also when starting to spin on a machine, to insert empty spool cores into the spinning units to which then, at each spinning unit, the spun double yarn is guided by means of a suction gripper. The spool core grips the double yarn by means of adhesive force and starts the winding-up. In the known construction, it is also provided for repairing a yarn breakage that the double yarn wound up on the spool core is gripped, unwound and placed in a splicing device, into which the newly spun double yarn is also placed. In the splicing device, a spliced connection is produced, after which the winding-up process is restarted.
An objective of the invention is to simplify the automatic exchange of yarn packages and spool cores at the spinning units of a spinning machine of the above-mentioned type.
In the case of the process, this objective is achieved in that the winding-up is interrupted, the full yarn package of the spinning unit is taken out of the devices for the winding-up and is replaced by a spool core having a starter winding with a starter yarn, and in that the double yarn coming from the devices for the spinning and the starter yarn are placed in a splicing device and are spliced together with one another, after which the winding-up is restarted.
By means of this development, it is achieved that the operations during the automatic exchange of yarn packages and spool cores correspond as much as possible to the operations during an automatic yarn breakage repair, so that only for the exchange of the yarn packages and spool cores, additional devices must be provided for the removal of the full package and for replacing it with the spool core equipped with the starter winding. The remainder of the operations required for the exchange of yarn packages and spool cores and for the restarting of the spinning unit may be carried out by devices which are also used for a piecing after a yarn breakage of one or both yarns. As a result, important constructive simplifications are achieved since the operations are standardized.
In a spinning machine, this objective is achieved in that devices are provided for separating a full yarn package from the devices for the winding-up as well as devices for replacing the full yarn package with a spool core having a starter yarn, a splicing device, devices for placing the starter yarn and the double yarn coming from the devices for the spinning in the splicing device and devices for rewinding the double yarn connected with the starter yarn and for transferring the spool core to the devices for the winding up of the spinning unit.
In a further development of certain preferred embodiments of the invention, it is provided that a single yarn is provided as the starter yarn with a strength that is increased with respect to the double yarn and/or of a coarser yarn size. A starter yarn of this type has the advantage that, on the one hand, it can have a higher strength and, on the other hand, mainly on the spool core equipped with the starting winding, can be found relatively easily by means of an automatic searching device and can be withdrawn from the spool core. In this case, it must, however, be provided that the twisting process is carried out such that the feeding package is maximally used up during the twisting-together only up to the starter winding.
In another preferred embodiment, it is provided that, as the starter yarn, a double yarn is used which, with respect to the material and the thickness, corresponds to the double yarn produced by the devices for the spinning. This has the advantage that each of the produced yarn packages, during the twisting, can be used up to the end including the starter winding. In order to facilitate the finding for an automatic device also in this development, it is provided in a further development of the invention that the ends of both yarns that form the double yarn serving as the starter yarn are connected with one another. As a result, it is ensured that the two components of the double yarn are withdrawn simultaneously. In a further development, it is provided that the end of the starter yarn is reinforced.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.